Methods and devices for universal braking, safe start protection, and other motor control for alternating current devices

ABSTRACT

Included herein is a circuit comprising resistors, capacitors, relays, diode bridges, TRIACs, and DIACs mounted to a substrate. The circuit may be electrically connected to a user device containing a wide range of types and specifications of AC induction motors. The circuit may be installed “plug-and-play” onto a user device, without the need for tools, custom installation or deconstruction of a user device. Upon user direction or automatically, the circuit may inject DC current into the user tool which generates a stationary magnetic field inside the AC induction motor causing deceleration/arrestment of the AC induction motor&#39;s rotor. The circuit may prevent unintended acceleration of the rotor upon powering on the user device. Also included is a method for prevention of unintended acceleration of the rotor upon powering on the user device. Also included is a method for decelerating/arresting an AC induction motor.

PRIORITY

This application claims the benefit of U.S. Provisional PatentApplication No. 62/503,096 entitled “Universal Plug and Play ACInduction Motor Brake and Safe Start Device” by the same inventor, filedon 8 May 2017, which is incorporated by reference as if fully set forthherein.

BACKGROUND OF THE INVENTION Field of Invention

Embodiments of the present disclosure relate generally to motor controland more specifically, to the safe deceleration and arrestment of movingmachinery, prevention of accidental or unintentional device startup, andsimple and universal installation.

Description of Related Art

Devices currently exist that decelerate and arrest rotating machinery,such as friction brakes and the like. This can be useful in situationsin which the machinery includes a tool-equipped rotor (e.g., drill, saw,grinder) that, when rotating at high speed, can cause injury ordestruction if movement is not ceased within a predetermined time frame.Furthermore, ceasing movement of a spinning tool can be difficult whenthe machine has a high rotational inertia, and such devices may bedifficult to install and require frequent replacement parts. Inaddition, mechanical braking devices often require custom installationfor each machine, which can prove costly.

Furthermore, devices currently exist that mitigate the danger inscenarios in which a machine with spinning parts can be unintentionallyactivated, or can begin operating without notice to people within theoperational area of the machine. However, these devices may not includeoperational modes to allow for safe usage. Clearly, what is needed inthe art is a low-maintenance, easy-to-install system that allows forsafer operation of rotating machinery.

SUMMARY OF THE INVENTION

Disclosed herein are embodiments that allow for safe and effectivedeceleration and arrestment of dangerous user devices with highrotational inertia that continue spinning long after the user device hasbeen powered down, such user devices include but are not limited to:band saws, table saws, disc sanders, drum sanders, grinders and otherrotating or reciprocating machinery.

Embodiments described herein allow for active arrestment of rotation ofa user device in cases in which an emergency stop is required.Embodiments described herein allow for a brake activation means to beintegrated (in whole or in part) with a designated emergency stopfeature.

Embodiments described herein decelerate and arrest the rotation of userdevices equipped with AC induction motors, cause low impact on motorperformance and lifetime, limit the need for replacement parts and/ormaintenance, and prevent unwarranted or unintentional activation of ACinduction motors.

Embodiments described herein allow for easy installation with little orno additional wiring or parts. In some instances, embodiments describedherein can be installed merely by plugging in a user device into afemale receptacle connected to embodiments described herein, and thenplugging the male receptacle of embodiments described herein into apower outlet.

Embodiments described herein describe a device that allows for saferactivation of a user device. Embodiments described herein integrate a DCinjection brake for a user device equipped with an AC induction motor.Some simplified embodiments allow for little or no active sensing, solidstate or complex digital control circuitry to sense the state of a userdevice power state or AC motor rotational state.

Embodiments described herein allow for simple and easy calibration of aDC injection brake by a user in order to provide the appropriate brakingtorque values for a user's AC induction motor-equipped device.Embodiments described herein may auto-calibrate without the need foruser input as described herein. Furthermore, embodiments describedherein may prevent or reduce overload, overheating, excessive wear, ordecreased lifespan/meantime to failure, of a user device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a motor brake and safe start system connected to auser device, according to embodiments described herein;

FIG. 2A illustrates a circuit schematic, according to embodimentsdescribed herein;

FIG. 2B illustrates a circuit schematic, according to embodimentsdescribed herein; and

FIG. 3 illustrates a method for switching between operational states,according to embodiments described herein.

DETAILED DESCRIPTION

Generality of Invention

This application should be read in the most general possible form. Thisincludes, without limitation, the following:

References to specific techniques include alternative and more generaltechniques, especially when discussing aspects of the invention, or howthe embodiment might be made or used.

References to “preferred” techniques generally mean that the inventorcontemplates using those techniques, and thinks those techniques arebest for the intended application. This does not exclude othertechniques for the invention, and does not mean that those techniquesare necessarily essential or would be preferred in all circumstances.

References to contemplated causes and effects for some implementationsdo not preclude other causes or effects that might occur in otherimplementations.

References to reasons for using particular techniques do not precludeother reasons or techniques, even if completely contrary, wherecircumstances would indicate that the stated reasons or techniques arenot as applicable.

Furthermore, the invention is in no way limited to the specifics of anyparticular embodiments and examples disclosed herein. Many othervariations are possible which remain within the content, scope andspirit of the invention, and these variations would become clear tothose skilled in the art after perusal of this application.

Glossary

In some embodiments, the term “safe start device” (and similar terms andphrases) may indicate embodiments that prevent the unintentional startupof a user device, (by way of example and not limitation, during aninterruption of power) for the purpose of user and operator safety.

The term “AC induction motor-equipped user device”, “user device”, andsimilar terms and phrases, may generally indicate a user device thatcontains an integrated AC induction motor. Such devices include but arenot limited to band saws, table saws, disc sanders, drum sanders,grinders and other fabrication equipment, and rotating or reciprocatingmachinery.

The term “Access Control” may refer to control circuitry which users canuse to restrict unintended access to the user device and embodimentsdescribed herein. By way of example and not limitation, embodimentsdescribed herein may prevent a user device from being used by anunauthorized user (e.g. a digital or physical key).

The term “cloud,” or “cloud computing” may refer to shared pools ofcomputer system resources or a human machine interface (HMI) accessiblethrough the Internet. These resources may be modular, or redundant, maytake the form of software as a service (SaaS). Despite the possibilitythat the location and/or deployment method of these resources may beunknown or determined by a third party, the resources themselves arestill accessible to embodiments described herein.

The abbreviations “A,” “V,” “AC,” and “DC,” as used herein areequivalent to, respectively, amps, volts, alternating current, directcurrent. Any other abbreviations used herein are intended to reflectstandard abbreviations used in the electrical arts.

The terms rest (noun), arrest (verb), arresting, arrestment (noundescribing process) may refer to the cessation of motion. As usedherein, cessation of motion may refer to the complete deceleration of aspinning object (e.g., the rotor of an AC induction motor).

The terms “effect”, “with the effect of” (and similar terms and phrases)generally indicate any consequence, whether assured, probable, or merelypossible, of a stated arrangement, cause, method, or technique, withoutany implication that an effect or a connection between cause and effectare intentional or purposive.

The term “relatively” (and similar terms and phrases) generallyindicates any relationship in which a comparison is possible, includingwithout limitation “relatively less”, “relatively more”, and the like.In the context of the invention, where a measure or value is indicatedto have a relationship “relatively”, that relationship need not beprecise, need not be well-defined, need not be by comparison with anyparticular or specific other measure or value. For example and withoutlimitation, in cases in which a measure or value is “relativelyincreased” or “relatively more”, that comparison need not be withrespect to any known measure or value, but might be with respect to ameasure or value held by that measurement or value at another place ortime.

The term “substantially” (and similar terms and phrases) generallyindicates any case or circumstance in which a determination, measure,value, or otherwise, is equal, equivalent, nearly equal, nearlyequivalent, or approximately, what the measure or value is recited. Theterms “substantially all” and “substantially none” (and similar termsand phrases) generally indicate any case or circumstance in which allbut a relatively minor amount or number (for “substantially all”) ornone but a relatively minor amount or number (for “substantially none”)have the stated property. The terms “substantial effect” (and similarterms and phrases) generally indicate any case or circumstance in whichan effect might be detected or determined.

The terms “this application”, “this description” (and similar terms andphrases) generally indicate any material shown or suggested by anyportions of this application, individually or collectively, and includeall reasonable conclusions that might be drawn by those skilled in theart when this application is reviewed, even if those conclusions wouldnot have been apparent at the time this application is originally filed.

FIG. 1

FIG. 1 illustrates a motor brake and safe start system connected to auser device, according to one embodiment. FIG. 1 is a high-leveloverview of embodiment as described herein. FIG. 1 includes smartbraking system 100 and user device 160, as delineated by dashed-lineenclosed boxes.

Motor Brake and Safe Start System (Smart Braking System) 100

Motor brake and safe start system (referred to herein as “smart brakingsystem 100”) includes safe start control circuit 105, adjustable powersupply 110, power switching control 115, braking torque adjustment means120, operation status indicator 125, brake activation means 130,electrical connection 145 and electrical connection 140.

In some embodiments, safe start control circuit 105, adjustable powersupply 110, and/or power switching control 115 may assist in managingdifferent modes provided by embodiments described herein, including oneor more of the following, but not limited to: braking mode, safe mode,standby mode, motoring mode (normal operation), reset mode as well asany modes as described herein. In one embodiment, power switchingcontrol 115 switches supplied electrical power from one source (e.g., ACmains) to a second source. In further embodiments, this second source iselectrical power received from one or more of: safe start controlcircuit 105, adjustable power supply 110, or any other circuit elementas described herein.

In some embodiments, adjustable power supply 110 converts AC electricity(e.g., AC mains power, 110 VAC, or any known AC electricity) into DCelectricity (e.g., full-wave rectified DC, half-wave rectified DC, orany known DC electricity).

In some embodiments, braking torque adjustment means 120 may take theform of a turnable dial, “knob-style,” “trimmer” potentiometer (i.e.,“trim-pot” or “turn-pot”) or variable resistor, but any and all means ofadjusting an electrical signal are contemplated by the inventor,including but not limited to: physical inputs, software apps,microcontroller outputs, mobile device apps, control signals sent by anHMI or cloud server.

In some embodiments, operational status indicator 125 displays thestatus of embodiments described herein. By way of example and notlimitation, statuses include operation modes as described herein (e.g.,braking, motoring, reset, safety and standby modes). While operationstatus indicator 125 takes the form of an LED as pictured in FIG. 1, theinventor contemplates the usage of any and all informative displays, byway of example and not limitation: lights, sounds, A/V displays LEDdisplays, televisions, HMI displays, desktop computer alerts, mobile appnotifications, etc.

In some embodiments, brake activation means 130 may take the form of apress button-style electrical contact, but any and all means ofactivating an electrical signal is contemplated by the inventor,including but not limited to: physical inputs, software apps, mobiledevice apps, control signals sent by an HMI or cloud server.

In some embodiments, electrical connection 145 may be a femalereceptacle (grounded or ungrounded), electrical connection 140 may be amale plug (grounded or ungrounded), and electrical connection 140 mayreceive electricity from wall socket 147, or any source of electricityknown in the art.

In some embodiments, electrical connections 140 and 145 may take theform of US standard 15 A, 110V, single-phase AC electrical connectors,but any and all forms of electrical connections with variouscompatibilities as required by regional standards are contemplated bythe inventor, including but not limited to: 220 volt single-phase AC, orAC current provided by an inverter coupled to a battery (e.g., as in anelectric vehicle).

In further embodiments, electrical connection 140 is connected to one ormore of adjustable power supply 110, safe start control circuit 105, orany other circuit element as described herein.

User Device 160

User device 160 includes electrical connection 165, user device powerswitch 170, and AC-induction motor 175.

In some embodiments, electrical connection 145 may be attached to userdevice electrical connection 165. In these embodiments, smart brakingsystem 100 supplies various types of electrical power to user device 160as described herein. In further embodiments, electrical connection 165may be a male plug (grounded or ungrounded), and electrical connection140 may receive electricity from wall socket 147, or any source ofelectricity known in the art. In further embodiments, electricalconnections 140 and 145 may take the form of US standard 15 A, 110V,single-phase AC electrical connectors, but any and all forms ofelectrical connections with various compatibilities as required byregional standards are contemplated by the inventor, including but notlimited to: 220 volt single-phase or multi-phase AC, or AC currentprovided by an inverter supplied by a battery (e.g., as in an electricvehicle).

In another embodiment, electrical connectors 140, 145, 165 and anyelectrical connectors mentioned herein may include a physically-lockingplug enclosure to prevent unplugging of embodiments described hereinfrom user device 160. In a further embodiment, this enclosure mayencapsulate male and female electrical connectors mentioned herein.

In some embodiments, user device 160 may contain or be attached to an ACinduction motor, upon which embodiments described herein will operate(e.g., supply various types of electrical power). By way of example andnot limitation, user device 160 may be a hand-held tool such as a powersaw, impact hammer, etc., or a table- or floor-mounted tool such as aband saw, lathes, etc., or sizable units such as CNC mills, laser orplasma cutters, etc. Embodiments described herein may be used todecelerate and/or arrest AC motors of any size, from small, high-speedAC motors up to and including vehicle drivetrains (e.g., electric cars,passenger/freight train drives, passenger/freight ship/submarine drives,airborne vehicles such as airplane/helicopter/drone drives, etc.).Embodiments described herein are not limited to these devices; indeedembodiments described herein may be used with any AC inductionmotor-enabled device, and the inventor contemplates all such devices.

In some embodiments, access control methods may be implemented toprevent unauthorized use of embodiments described herein. For example,an RFID-enabled tag (not pictured) may be used in conjunction with anRFID reader (not pictured) connected to embodiments described herein inorder to confirm that an authorized user is attempting to accessembodiments described herein.

Modularity/Integrability of Embodiments Described Herein

While FIG. 1 displays smart braking system 100 and user device 160 asseparate entities with electrical plugs (by way of example and notlimitation connections 140, 145 and 165), those skilled in the art willunderstand that any and all electrical connections, including anyelectrical connections as described herein, to be merely descriptive andexemplary. More specifically, those of skill in the art will realizethat any and all electrical connectors or connections as describedherein can be simplified, thus allowing for integration of embodimentsdescribed herein with or within a user device. The inventor contemplatesthat embodiments described herein may be integrated directly into, e.g.,a power tool, table-mounted tool, or any AC induction motor-enableddevice mentioned herein and/or as known in the art. By way of exampleand not limitation, smart braking system 100 may be miniaturized andintegrated into the handle of a rotary saw, or integrated into ajunction box supplying power to a large AC motor (e.g., mill, lathe,etc.).

In contrast, embodiments described herein may be a separate, connectablemodule as shown in FIG. 1, including detachable plugs. In other words,embodiments described herein may be modular, and thus may be detachedfrom a user device and moved to another user device. In one embodiment,smart braking system 100 may be ‘unplugged’ from a user device 160 andconnected to another user device 160.

Output Current/Voltage Adjustments to AC Induction Motors

Embodiments described herein allow for effective DC injection to, andthus braking of, an AC induction motor without the need for activesensing, solid state or digital control circuitry to monitor orotherwise sense the state of the user device (e.g., user device powerswitch 170) or the current operational state of the user device ACinduction motor (e.g., AC induction motor 175).

While some embodiments described herein do not require adjustments orsensing, the inventor contemplates embodiments that allow foradjustments of embodiments outputs to match the characteristics of aconnected user device.

Embodiments described herein (by way of example and not limitation,smart braking system 100) may be adjusted by a user to better service auser device 160, by way of example and not limitation, smart brakingsystem 100 may be tuned or programmed to supply a current/voltagecombination (e.g., DC-injection) that comports with acurrently-connected user device 160. In this embodiment, controlsdescribed herein, by way of example and not limitation, include brakingtorque adjustment means 120 which may be used to adjust the output ofembodiments described herein to better service various user devices.

In some embodiments, smart braking system 100 may, by way of example andnot limitation, also include DC waveform adjustments (full-waverectified, half-wave rectified, high frequency switching, magnitude,frequency, etc.) in order to better service various user devices.

In some embodiments, smart braking system 100 may, by way of example andnot limitation, also include adjustment for the period of time in whichbraking torque is being applied, as would be required for a single-pressentry into the braking mode of operation. Such user adjustment (notpictured) may take the form of a turnable dial, “knob-style,” “trimmer”potentiometer (i.e., “trim-pot” or “turn-pot”) or variable resistor, butany and all means of adjusting an electrical signal are contemplated bythe inventor, including but not limited to: physical inputs, softwareapps, microcontroller outputs, mobile device apps, control signals sentby an HMI or cloud server.

Embodiments described herein (by way of example and not limitation,smart braking system 100) may be computer-programmed with multiplecurrent/voltage combinations to allow for quick-selection (e.g., by auser/computer) of pre-determined output settings to match smart brakingsystem 100 output to a user device 160. By way of example and notlimitation, pre-determined output settings may be stored as computerinstructions (e.g., software/firmware) in memory (not pictured) (e.g.,local/remote EEPROM, RAM, flash memory/hard drive/solid state drive, onthe Internet or in the Cloud).

Embodiments described herein (by way of example and not limitation,smart braking system 100) may include an auto-detect feature (notpictured) that allows for detection by embodiments described herein (byway of example and not limitation, smart braking system 100) of a userdevice. In this manner, smart braking system 100 may automaticallydetermine the input requirements for DC injection or othercurrent/voltage combinations that are distinct and appropriate for anindividual or range or AC induction motors, executed with reduced or noaction by a user. Determination or reception of the specifications of aconnected AC induction motor may be communicated through known wired orwireless data transfer means, by way of example and not limitation, USB,Bluetooth, Ethernet, RS-232, WiFi (2.4 GHz, 5 GHz), WiGig, (60 GHz),analog motor classification, etc. In one embodiment, an AC inductionmotor connected to a smart braking system 100 may send information tothe smart braking system 100 by the above means, thus allowing smartbraking system 100 to automatically adjust an output to acurrent/voltage combination appropriate for that AC induction motor. Inanother embodiment, the smart braking system 100 may contain voltage andcurrent sensing means by which to characterize the impedance of themotor through an automatic test sequence and without input from a user,thereby automatically detecting optimal braking torque and delivering anoptimized current/voltage combination appropriate for that AC inductionmotor.

Embodiments described herein (by way of example and not limitation,smart braking system 100) may receive and/or store information about aconnected AC induction motor or user device through an interconnectednetwork of devices, including but not limited to, multipleimplementations of smart braking system 100, sensors, HMIs, computers,entities connected to the Internet (e.g., “Internet of Things”/IoT) orthroughout the Cloud. By way of example and not limitation, accesscontrol, machine run time and system notifications may be enabled usingthe Cloud. In one embodiment, access to embodiments described herein maybe restricted to authorized users (who log into e.g., a user's mobiledevice linked to a cloud account associated with embodiments describedherein). In a second embodiment, operation time of embodiments describedherein may be displayed on e.g., a user's mobile device. In a thirdembodiment, system information pertaining to embodiments describedherein may be sent as notifications that are populated on a user'smobile device. In another embodiment, multiple instances of embodimentsdescribed herein may be linked to each other and share data as describedherein with each other as well as other entities (e.g., HMIs, sensorsused in factory automation, mobile devices owned by other authorizedusers who have cloud accounts associated with embodiments describedherein) in an IoT environment. In another embodiment, user deviceinformation may be used to advise users on compliance or generateautomatic reporting such as would be the case in federally-mandatedfabrication and maintenance facilities.

Furthermore, while any element in FIG. 1 or elsewhere as describedherein (by way of example and not limitation, braking torque adjustmentmeans 120 or operation status indicator 125) may be illustrated asseparate or exterior to smart braking system 100, these elements may beintegrated in any manner with any other embodiments as described herein.By way of example and not limitation, braking torque adjustment means120 may be (1) mounted directly on smart braking system 100; (2) mountedon user device 160; or (3) integrated into a wall panel or Human MachineInterface (HMI) used to control large AC induction motors (e.g., on anassembly line).

In addition, those skilled in the art will understand that, ifelectrical power supply and load requirements are met, there isvirtually no limitation on the number or type of user devices connectedto a single unit of embodiments described herein. While FIG. 1 displaysone example of a user device 160, those skilled in the art willappreciate that embodiments described herein may supply electricity (byway of example and not limitation, in the form of DC-injection) tomultiple AC induction motors of varying size and type. In oneembodiment, the inventor contemplates including multiple outputs fromsmart braking system 100. In a further embodiment, embodiments describedherein may include multiple outputs may supply DC-injection or othercurrent/voltage types that are tailored to AC induction motors. Thistailoring may be chosen to cause by way of example and not limitation,enhanced deceleration or arrestment, reduced wear or increasedperformance of the AC induction motor.

An alternative embodiment contemplated by the inventor is forembodiments described herein to be placed within the user's device as auniversal module, supplied by the original equipment manufacturer of theuser device. In this embodiment, embodiments described herein may beelectrically situated between user device power switch 170 andAC-induction motor 175 and/or directly integrated into a user device. Inthis manner, control electronics that may be required for operation ofembodiments described herein may be simplified. Further in thisembodiment, embodiments described herein may automatically actuate userdevice power switch 170, as well as automatically apply braking torquewhen the user power switch 170 is manually actuated. Further in thisembodiment, applied braking torque can be timed to achieve adequaterotor deceleration/arrestment. In additional embodiment, an activesensor may be used to ensure complete AC induction motor rotorarrestment has occurred. The inventor contemplates any and all sensorscapable of this action, by way of example and not limitation, rotation,proximity, laser, fiber optic, vibrational sensors, accelerometers andany sensors known in the art.

In another embodiment, a package including some or all standard partsassociated with embodiments described herein may be provided as a DIYkit for users to self-install a custom or permanent version ofembodiments described herein.

In another embodiment, an embedded machine switch control device may beincluded to effectively override the user device power switch 170 tosimplify control procedures provided herein.

In some embodiments throughout the disclosure, embodiments describedherein may be intended to remain connected to a user device (by way ofexample and not limitation, supplying AC and/or DC power as describedherein from embodiments described herein to the user device) in orderfor embodiments described herein to operate as described herein.

The above illustration provides many different embodiments forimplementing different features of the invention. Specific embodimentsof components and processes are described to help clarify the invention.These are, of course, merely embodiments and are not intended to limitthe invention from that described in the claims.

FIGS. 2A and 2B

FIGS. 2A and 2B illustrate a circuit schematic, according to oneembodiment. FIG. 2A illustrates adjustable power supply 200, whichincludes resistors 202, 204, 206, and 208, hot supply 210, neutralterminal 212, optional circuit protection device 216, diode bridges 218and 220, capacitors 224 and 226, variable resistor 228, contact A 232and contact B 234, DIAC 236, and TRIAC 238.

In one embodiment, hot supply 210 may be AC mains power, and neutralterminal 212 may be a return current path. In one embodiment, optionalcircuit protection device 216 may protect embodiments described hereinfrom current/voltage overload, and may be by way of example and notlimitation, a fuse or circuit breaker.

In one embodiment, capacitor 224, resistor 206, variable resistor 228,and DIAC 236 may have their values chosen to set the firing angle rangeof TRIAC 238. In one embodiment, TRIAC 238 may control the flow ofcurrent from the hot supply 210 to the bridge rectifier 220. Thoseskilled in the art will realize that TRIAC 238 controls the relativemagnitude of the DC voltage presented across terminal B 234 and terminalA 232, thereby regulating the braking torque imposed onto a user device.In further embodiments, diode bridge 218, in conjunction with resistors202 and 204, may remove residual charge from capacitor 224 as the linevoltage switches polarity. In one embodiment, this may ensure aconsistent starting voltage for capacitor 224 on each half cycle of theAC mains power, may prevent ‘snap-on’ behavior of the adjustable powersupply, and may allow for improved low-power performance of theadjustable power supply.

In one embodiment, diode bridge 220 may full-wave rectify an output. Ina further embodiment, adjustable power supply 200 forms a full waverectified AC chopper circuit capable of converting AC power into DCpower of adjustable magnitude.

In one embodiment, variable resistor 228 may be used by a user to adjustthe braking torque output by embodiments described herein. In a furtherembodiment, a user may adjust variable resistor 228 with, by way ofexample and not limitation, an adjustment means such as a turnable dial,“knob-style,”“trimmer” potentiometer (i.e., “trim-pot” or “turn-pot”),or any adjustment means as described herein. In a further embodiment,variable resistor 228, in conjunction with resistor 206, capacitor 224,and DIAC 236 may have a value chosen to set a minimum and maximum rangeof output DC voltage, which, in some embodiments, may be used as DCinjection current fed into an AC induction motor. In this manner,braking torque may be adjusted. Furthermore, resistor 206 may have aresistance to set the minimum and maximum range of the power circuit.

In one embodiment, capacitor 226 forms an RC snubber circuit withresistor 208, wherein the capacitance and resistance may be chosen topartially or completely dissipate inductive voltage spikes withinembodiments described herein.

FIG. 2B

FIG. 2B illustrates safe start control circuit 240, power switchingcontrol 260, indicator lamps 280, brake activation means 290.

Safe Start Control Circuit 240

In one embodiment, safe start control circuit 240 receives power fromhot supply 242, which may be AC mains power. In one embodiment, safestart control circuit 240 includes relay 244, which contains a firstnormally open contactor 246 and a second normally open contactor 248. Ina further embodiment, contactor 246 and contactor 248 may besimultaneously operated by excitation of a single coil associated withrelay 244, as illustrated by a symbolic dashed line and downwardpointing half arrow.

In a further embodiment, safe start control circuit 240 includes relay254, which contains normally closed contactor 256 and normally opencontactor 258. In a further embodiment, contactor 256 and contactor 258may be simultaneously operated by excitation of a single coil associatedwith relay 254, as illustrated by a symbolic dashed line and downwardpointing half arrow.

In a further embodiment, a current path to connector 292 may be formedfrom the hot supply 242 through contactor 246, contactor 256, and switch262. In a further embodiment, as will be realized by those skilled inthe art, the coil of relay 244 may be latched to neutral, therebyexciting relay 244, through contactor 258 and/or contactor 248 andswitch 266.

Power Switching Control 260

In one embodiment, power switching control 260 includes switches 262,264 and 266, as well as relay 268. In one embodiment, switches 262, 264and/or 266 may take the form of double throw contactors, SPDTcontactors, or any other electrical switching means known in the art. Ina further embodiment, switches 262, 264 and 266 are simultaneously ormutually operated by excitation of a single coil associated with relay268, as illustrated by a symbolic dashed line and downward pointing halfarrow.

In an another embodiment, the common terminal of brake activation means290 is connected to neutral terminal 212 and the normally-open terminalof switch 290 is connected to the coil of relay 268. In a furtherembodiment, the coil of relay 268 may also be connected to hot supply242.

In a further embodiment, the common terminal of switch 262 may beconnected to connector 292, the normally-open terminal of switch 262 maybe connected to contact B 234, and the normally-closed terminal ofswitch 262 may be connected to contactor 256, the coil of relay 254, andindicator 282.

In a further embodiment, the common terminal of switch 264 may beconnected to connector 292, the normally-open terminal of switch 264 maybe connected to contact A 232, and the normally-closed terminal ofswitch 264 may be connected to neutral terminal 212.

In a further embodiment, the common terminal of switch 266 may beconnected to neutral terminal 212 and the normally-closed terminal ofswitch 266 may be connected to contactor 248. In one embodiment,switches 262 and 264 may be connected to electrical connection 292. Inone embodiment, electrical connector 292 may be a female electricalreceptacle that allows a user device to be connected to electricalconnection 292. In a further embodiment, electrical connector 292 has atleast one connection to ground terminal 294. In further embodiments,electrical connection 292 may take the form of a US standard 15 A, 110V,single-phase AC electrical connector, but any and all forms ofelectrical connections with various compatibilities as required byregional standards are contemplated by the inventor, including but notlimited to: four or more pole connectors, 220 volt single-phase ormulti-phase AC, or AC current provided by an inverter coupled to abattery (e.g., as in an electric vehicle).

Indicators 280

In one embodiment, indicators 280 includes indicator 282 and indicator284. Indicator 282 may be connected to hot supply 242 as well as thecoil of relay 254, contactor 256, and the normally-closed terminal ofswitch 262. Indicator 284 is connected to hot supply 242 as well asneutral terminal 212.

In one embodiment, indicators 280 may display statuses of embodimentsdescribed herein. While indicator 282 and indicator 284 are illustratedas LEDs, the inventor contemplates all methods of status indication,including those described herein and as known in the art. In oneembodiment, indicator 284 may illuminate to indicate that AC power hasbeen provided to embodiments described herein. In one embodiment,indicator 282 may illuminate to indicate that embodiments describedherein are in safe mode 320 and that a user device switch is powered onand may need to be reset.

In one embodiment, brake activation means 290 may include a switch toallow a user to control a DC injection brake and supply DC power to anattached AC induction motor-equipped user device, as described herein.

Safe Mode Circuit Path Execution 80. Embodiments follow that describevarious operational modes of embodiments described herein. If, duringinitial startup, the user device is switched to a “power on” state,embodiments described herein may enter a first operational state: safemode. In one embodiment, safe mode may provide protection against anunintended powering on of an attached user device when power is restoredto the user device (after, e.g., a power interruption). In a furtherembodiment, safe mode is actuated by the neutral terminal of the coil ofrelay 254 being connected to neutral terminal 212 through switch 262,electrical connector 292, electrical connector 165, user device powerswitch 170, and the winding of user device AC induction motor. In oneembodiment, relay 254 may have a coil impedance selected such thatexcitation of relay 254 can be maintained for a wide range of ACinduction motor impedances.

In one embodiment, excitation of relay 254 opens contactor 256, whichmay thereby preemptively and materially disconnect a user device fromthe hot supply. Furthering this embodiment, relay 244 is simultaneouslyexcited, by the closure of contactor 258. The excitation of relay 244closes contactor 246, and thereby readies embodiments described hereinby supplying AC power to the common terminal of contactor 256.

The excitation delays of relays described herein may be selected andcoordinated to prevent a race condition where contactor 246 could closebefore contactor 256 could open. The excitation of relay 244 may alsolatch relay 244 through contactor 248, thereby releasing dependence ofrelay 244 on the state of relay 254. While in safe mode, indicator 282many also connect to neutral terminal 212 to indicate safe mode status.

Reset Mode Circuit Path Execution

In one embodiment, if upon initial powering up of embodiments describedherein, the user device is switched to a “power off” state, embodimentsdescribed herein may enter a second operational mode: reset mode. In oneembodiment, reset mode alerts the user of the presence of a DC injectionbraking unit, and, in a further embodiment, may require the user toperform an initial arming sequence to return embodiments describedherein to return to a normal operational state.

In a further embodiment, reset mode may be a default state in whichrelay 244 may remain unexcited, thereby keeping contactor 246 open, andmay prevent the flow of some or all of power from hot supply 242. In anadditional embodiment, embodiments described herein may be armed byforcing embodiments described herein into safe mode (as describedherein) by turning the user device to an “on” state.

Standby Mode Circuit Path Execution

In one embodiment, if embodiments described herein are in safe mode (asdescribed herein) embodiments described herein can be put into thirdoperational state: standby mode. In this embodiment, embodimentsdescribed herein can be put into standby mode by switching the userdevice to a “power off” state. In a further embodiment, this action mayinterrupt the neutral path of relay 254, which may thereby de-exciterelay 254 and may close contactor 256 and open contactor 258, which maylatch relay 244 through contactor 258 to neutral terminal 212, which mayconnect electrical connection 292 to hot supply 242 for normal operationof a user device.

Motoring Mode Circuit Path Execution

In one embodiment, while embodiments described herein are in standbymode (as described herein), a user device may be operated normallythrough the use of the power switch connected to the user device,putting embodiments described herein in a fourth operational state:motoring mode. Thus, in this embodiment, the AC induction motorconnected to the user device may operate normally (as intended) whenembodiments described herein are in motoring mode. Further in thisembodiment, with brake activation means 290 is actuated, embodimentsdescribed herein may transition from motoring mode to braking mode,whereby a braking torque can be applied (as described herein).

Braking Mode Circuit Path Execution

While in motoring mode, reset mode, or standby mode, embodimentsdescribed herein may enter a fifth operational state: braking mode. Inone embodiment, braking mode may engaged when brake activation means 290is actuated. In this manner, the operation of brake control 290 mayfunction to decelerate or arrest the rotor of a user device connected toelectrical connection 292.

In one embodiment, the activation of brake control 290 may excite relay268, which may thereby switch the common of contactors 262 and 264 tocontact B and A, respectively, which, in one embodiment, may beconnected to DC from adjustable power supply 200. Further in thisembodiment, the activation of brake control 290 may interrupt thelatching circuit of relay 244 through contactor 266, thereby preventingthe simultaneous connection of AC mains 242 and the adjustable powersupply 200 to connection 292. Further in this embodiment, the subsequentrelease of brake control 290, may return embodiments described herein tosafe mode (as described herein).

In one embodiment, when in braking mode, embodiments described hereinmay introduce a regulated DC voltage into the AC induction motor of auser device, effectively utilizing DC injection to decelerate or arrestthe rotor and attached tooling to the AC induction motor. Duringactivation of brake activation means 290, DC power may be producedwithin adjustable power supply 200 and may be switched throughcontactors 262 and 264. Within adjustable power supply 200, AC power maybe regulated through TRIAC 238 as part of a phase-controlled AC choppercircuit, which may then be rectified into chopped, full-wave rectifiedDC power. In a further embodiment, braking torque supplied byembodiments described herein may be calibrated through variable resistor228 as described herein. In one embodiment, resistor 206 and variableresistor 228 have values selected to provide a braking torque rangesuitable for attached user devices and to prevent overload, overheating,excessive wear, or decreased lifespan/meantime to failure, of a userdevice. In an additional embodiment, variable resistor 228 are placed ina location accessible to the user.

While electromechanical devices (e.g., relays, switches, contactors,etc.) are pictured in FIG. 2B, those skilled in the art will appreciatethat some or all of these electromechanical devices may be replaced withsolid-state equivalents. By way of example and not limitation, switchesmay be replaced with other switching elements withvoltage/current/performance specifications suitable for the application(e.g., tuned for or compatible with a specific or range of AC inductionmotors). Any and all solid state equivalents are contemplated by theinventor, including but not limited to: MOSFETs, SCRs, TRIACs, BJTs,and/or microcontroller-actuated switches. Those of skill in the art willappreciate that elements in FIGS. 2A and 2B may be executed using eithera digital implementation (e.g., including a processor, memory and buscommunication system, etc.), or an analog implementation (e.g., controlcircuitry).

By way of example and not limitation, a closed-loop integral currentfeedback may be used to regulate DC output current of smart brakingsystems as described herein to the user device. Furthering thisembodiment, the inclusion of a current transformer, hall-effect sensor,or other proportional current-sensing device (not pictured) may be usedto effectively transition the DC injection output of the smart brakingsystem 100 from a voltage source to a current source, as will berealized by those skilled in the art. Furthering this embodiment, thecontrol circuitry needed to accomplish this regulation can be achievedthrough analog circuitry or by digital means.

In an additional embodiment, the DC injection output current of smartbraking systems as described herein may be ramped up to a final value.By way of example and not limitation, this ramped current output may belinear, logarithmic, or exponentially, starting at a magnitudesubstantially zero and ramping up to a final output value as describedherein. Furthering this embodiment, the output current may also rampdown at the conclusion of the braking action, starting at the brakingvalue and ramping down to substantially zero.

Some embodiments may be capable of receiving inputs as follows: 120 VACwith a continual current rating of 20 amps and a peak current rating of35 amps. Some embodiments may be capable of producing outputs asfollows: (1) 120 volts AC (by way of example and not limitation, instandby or motoring mode as described herein) with a current rating of20 amps continuous and 35 amps peak; (2) 10-170 volts DC (by way ofexample and not limitation, braking mode, as described herein) with abraking current rating of 15 amps continuous and 25 amps peak; and, (3)0 volts (reset or safe mode).

Some embodiments provide for safely starting (by way of example and notlimitation, safe start or smart braking, as described herein), stopping(by way of example and not limitation, braking mode, as describedherein), user devices with AC induction motors in the following ranges:(1) 110-220 VAC rating (2) DC motor impedances 0.3□-10□, (3) 1/16thhorsepower to 1.75 horsepower single phase induction motors; (4) motorconfigurations of one or more of the following types: capacitor start,capacitor run, capacitor start capacitor run, and/or split winding.

The inventor contemplates that electrical components used and describedherein may be of varying types, and those of skill in the art willappreciate that many electrical components may be interchangeable. Byway of example and not limitation, a list of exemplary component partsis provided that may be used in some embodiments as described herein.This is list is not exhaustive, and is given in following table:

TABLE 2.1 Element # Description Value Part No. 218 Bridge Rectifier 1amp rated ABS10A-13 224 Metal Film Capacitor 0.1 microfaradMKS2F031001E00JA00 226 Metal Film Capacitor 0.1 microfarad 104MKP275KD236 DIAC 32 V Trigger SMDB3 206 Resistor 70 kiloohms CR0805-FX-7152ELF208 Resistor 100 ohms ERJ-1TYJ101U 228 Potentiometer 100 kiloohms3309W-1-104 202 R-US_R0805 33 kiloohms ERJ-P06J303V 204 R-US_R0805 33kiloohms ERJ-P06J303V 238 High-Commutation TRIAC 25 Amp Q6025LH5TP 244,246, 248 DPDT RELAY DPDT RELAY 782XBXCT-120A 254, 256, 258 DPDT RELAYDPDT RELAY 782XBXCT-120A 268, 262, 264 3PDT RELAY 3PDT RELAY783XCXM4L-120A 216 Circuit Breaker 15 AMP 4404.0102 220 Bridge Rectifier35 amp rated KBU3510-G

FIG. 3

FIG. 3 illustrates a method for switching between operational states,according to embodiments described herein. Although the method steps aredescribed in conjunction with FIGS. 1-3, persons skilled in the art willunderstand that any system configured to perform the method steps, evenin a different order may fall within the scope of the presentdisclosure. Moreover, the steps in this method are illustrative only anddo not necessarily need to be performed in the given order they arepresented herein. In some embodiments, certain steps may be omittedcompletely.

The method 300 begins with step 310, in which a user device is initiallysupplied power. The method 300 diverges depending on the on/off state ofthe user device.

Reset Mode

If the user device is switched off, the method 300 proceeds to a step315 in which begins a reset mode, as described herein. In oneembodiment, reset mode may prevent user device operation in order tonotify user of the existence of embodiments described herein and/ordecelerates user device motor rotation. At this step 315, if no furtheraction is taken, embodiments described herein may remain in reset modeand the method 300 ends. If the user device is switched on, the method300 proceeds to a step 320, described below.

Safe Mode

Continuing from step 310 above, if the user device is switched on, themethod 300 proceeds to a step 320 which begins a safe mode, as describedherein. In one embodiment, safe mode prevents user device motor outputand/or decelerates user device motor rotation. If no further action istaken, embodiments described herein may remain in safe mode and themethod 300 ends.

If, however, in step 320, the user device is switched off, the method300 proceeds to a step 325, wherein embodiments described herein mayenter a standby mode. Alternatively, if the brake button is pressed andheld, embodiments described herein may enter a braking mode as describedherein and the method 300 proceeds to a step 330.

Standby Mode

At a step 325, user device output is in AC mode and user device motorrotation may be uninhibited by embodiments described herein. In oneembodiment, user device motor rotation may be coasting or at rest. If nofurther action is taken, the method 300 ends. If the user device isswitched back on, embodiments described herein may enter a motoring modeas described herein, and the method proceeds to a step 335.

Braking Mode

At a step 330, embodiments described herein output DC power to the userdevice. In one embodiment, the user device is an AC induction motorthat, upon receiving DC power, will decelerate the user device motorrotation. In other words, embodiments described herein act as anelectromagnetic brake since DC power will create a stationary magneticfield as opposed to the rotating magnetic field that occurs within ACinduction motors. In this manner, embodiments described herein maysafely and effectively decelerate the user device motor rotation ratherthan simply waiting for user device motor rotation to halt (based one.g., AC motor internal friction, eddy currents, drag, etc.).

If no further action is taken, the method 300 ends. If the brake buttonis released, embodiments described herein may enter safe mode and themethod returns to step 320.

Motoring Mode

At a step 335, the user device is in normal operation. In oneembodiment, the user device is switched on, delivering nominal AC powerto the user device and integral induction motor, causing motor rotation.If the brake button is pressed and held, embodiments described hereinmay enter braking mode as described herein, and the method 335 returnsto step 330. If no further action is taken, the method 300 ends.

Although the invention is illustrated and described herein as embodiedin one or more specific examples, it is nevertheless not intended to belimited to the details shown, since various modifications and structuralchanges may be made therein without departing from the spirit of theinvention and within the scope and range of equivalents of the claims.Accordingly, it is appropriate that the appended claims be construedbroadly and in a manner consistent with the scope of the invention, asset forth in the following claims.

I claim:
 1. A circuit for a smart braking system, the circuitcomprising: an electricity input connector; an electricity outputconnector configured to connect with an electrical connection of a userdevice having an AC motor; and a motor brake sub-system connected toreceive electricity from the electricity input connector and to outputelectricity to the electricity output connector, the motor brakesub-system including a sub-circuit including switches, which whentriggered, activate the motor brake sub-system to output DC power to theuser device, thereby applying a counter-rotational stopping torque tothe AC motor and decelerating rotation of a rotating component of theuser device, wherein the circuit has a plurality of functional statesincluding: a first state, activated via manual actuation of an onswitch, in which electricity is supplied to the user device to allowrotation of the rotating component, a second state, activated via manualactuation of a braking switch, in which the motor brake sub-system isactivated to decelerate the rotation of the rotating component, and athird state, activated once the rotating component has ceased rotation,in which no electricity is supplied to the user device to preventunintentional rotation of the rotating component.
 2. The circuit ofclaim 1, wherein the DC power output to the user device includes one ormore of: a braking voltage output of approximately 10 to approximately170 volts DC; an approximately continuous braking current output ofapproximately 15 amps; or a peak braking current output of approximately35 amps.
 3. The circuit of claim 1, wherein the AC motor of the userdevice is an AC induction motor.
 4. The circuit of claim 1, wherein thecircuit is configured to receive one or more of: a voltage input ofapproximately 120 volts AC; a continuous current input of approximately20 amps; or a peak current input of approximately 35 amps.
 5. Thecircuit of claim 1, further comprising a safe start sub-circuitconfigured to prevent unintentional startup of the user device after apower failure.
 6. The circuit of claim 5, wherein an output of the safestart sub-circuit, when triggered, is one of a voltage output ofapproximately 0 volts or a current output of approximately 0 amps. 7.The circuit of claim 1, wherein the one or more switches includes auser-manipulatable press-button electrical contact to activate braking.8. The circuit of claim 1, further comprising an adjustable power supplyincluding a hot supply connected to a diode bridge in series with aTRIAC.
 9. A method of a smart braking system for supplying electricityto a user device equipped with an AC motor, the method comprising stepsof: receiving electricity via an electricity input connector, theelectricity passing to the user device via an electricity outputconnector configured to connect with an electrical connection of theuser device; and outputting, upon detection of activation of a brake, DCpower to the user device via a motor brake sub-system connected toreceive electricity from the electricity input connector and to outputelectricity from the electricity output connector, thereby applying acounter-rotational stopping torque to the AC motor and deceleratingrotation of a rotating component of the user device, wherein the smartbraking system has a plurality of functional states including: a firststate, activated via manual actuation of an on switch, in whichelectricity is supplied to the user device to allow rotation of therotating component, a second state, activated via manual actuation of abraking switch, in which the motor brake sub-system is activated todecelerate the rotation of the rotating component, and a third state,activated once the rotating component has ceased rotation, in which noelectricity is supplied to the user device to prevent unintentionalrotation of the rotating component.
 10. The method of claim 9, furthercomprising a step of supplying a safe start output to the user deviceafter interruption of power.
 11. The method of claim 10, wherein thesafe start output is one of approximately 0 volts or approximately 0amps.
 12. The method of claim 9, wherein the step of outputting DC powergenerates a stationary magnetic field in the AC motor.
 13. The method ofclaim 9, wherein the step of outputting DC power includes one or moreof: a voltage of approximately 10 to 170 volts DC; a continuous brakingcurrent of approximately 15 amps; or a peak breaking current ofapproximately 25 amps.
 14. The method of claim 9, wherein the step ofoutputting DC power decelerates a rotor attached to the AC motor. 15.The method of claim 14, wherein the rotor is attached to a tool suchthat deceleration of the rotor decelerates rotation of the tool.
 16. Themethod of claim 14, wherein the rotor is attached to a tool such thatdeceleration of the rotor arrests the tool.
 17. The method of claim 14,further comprising a step of preventing operation of the user device.18. The method of claim 9, further comprising a step of detecting theactivation of the brake caused by a user-manipulatable press-buttonelectrical contact.
 19. A detachable and modular smart braking systemcomprising: a module that is separate from and connectable to a userdevice having an AC motor; an electricity input connector that is a maleplug attached to the module and configured to receive electricity; anelectricity output connector that is a female receptacle attached to themodule and configured to output electricity; and a motor brakesub-system within the module and connected to receive electricity fromthe electricity input connector and to output electricity from theelectricity output connector, the motor brake sub-system including asub-circuit including one or more switches, which when triggered, causethe sub-circuit to activate the motor brake sub-system to outputapproximately 10 to 170 volts DC or a braking current of approximately15 amps, thereby applying a counter-rotational stopping torque to the ACmotor and decelerating rotation of a rotating component of the userdevice, wherein the smart braking system has a plurality of functionalstates including: a first state, activated via manual actuation of an onswitch, in which electricity is supplied to the user device to allowrotation of the rotating component, a second state, activated via manualactuation of a braking switch, in which the motor brake sub-system isactivated to decelerate the rotation of the rotating component, and athird state, activated once the rotating component has ceased rotation,in which no electricity is supplied to the user device to preventunintentional rotation of the rotating component.
 20. The system ofclaim 19, further comprising a safe start sub-system configured toprevent unintentional startup of the user device after a power failure.